1 Field of the Invention
The invention is directed to a heavy-duty vehicle with a gripping device for picking up and moving a standardized load carrier which can be actuated by hydraulic cylinders and tipping-prevention means for the vehicle which are in operation during the movement of the load carrier.
2 Discussion of the Prior Art
A vehicle of the generic type is known from German Reference DE 36 05 665 C2. It is used for lifting, transporting and tipping a slag vessel, or the like, provided with side trunnions and is outfitted with a self-driven traction machine and a load transport part provided with wheels. A swiveling frame, serving to grip the trunnions and pick up the vessel, is mounted in a swivelable manner on the rear end of the loading part. The swiveling frame is moved by a hydraulic cylinder which occupies different positions for picking up, emptying and depositing the vessel.
A jib base which can telescope out hydraulically and which can be supported on the ground when the vessel is lifted or emptied by the swiveling frame is arranged at the end of the vehicle so that the vehicle is not subject to impermissible tilting moments or loading moments for the undercarriage as a result of the slag vessel to be swiveled over the rear. Further safety devices are not disclosed.
Road vehicles by which rubbish receptacles, for example, can be picked up and placed on a platform of the vehicle, likewise with a rear swiveling device, are known from practice. However, vehicles of this type generally have different emptying devices than those shown in DE 36 05 665 C2. In order that the vehicles can pick up the receptacles by the trunnions or similar stops, these load carriers must be standardized so that gripping devices can always find their target at the same position.
Although the empty (tare) weight is usually written on the receptacle, only the driver can estimate for himself whether or not the container is too heavy for the transport vehicle. This results in overloading of the vehicle beyond the permissible working load and also in a problem for the stability of the vehicle when lifting the receptacle.
Therefore, the problem addressed by the present invention is to increase the safety of load transporters of the type mentioned above and to give the driver information about the working load or safety hazards which might possibly occur. Overloading of or hazardous work with the load vehicle must also be eliminated.
The invention is based on the idea that work with heavy-duty transporters can lead to serious accidents as a result of carelessness on the part of the operator and that, therefore, the driver should be given information in every case about the working load to be handled for all working positions and loading work and, in every instance, incorrect operation based on erroneous appraisal of the situation should be prevented by appropriate automated functions of the vehicle.
For this purpose, according to the invention, at least one of the hydraulic cylinders of the gripping device, preferably the hydraulic cylinder used as a swiveling cylinder for the gripping device, is provided with switches, at least one of which engages a pressure detection device for the hydraulic pressure in the cylinder on one or both sides of the piston at a predefinable stroke of the piston. The pressure detection device switches on a safety device when a reference value for the pressure, which can be preset, is exceeded.
The safety device can be an optical or acoustic signal transmitter for the driver or can also comprise a plain text display or indicator which, in addition, also lights up in color.
In addition, the safety device should comprise a supporting base for the vehicle frame, which safety device, when engaged, activates the supporting base depending on a signal from the pressure detection device. This need not be carried out automatically, but rather can also be triggered manually by the driver. Naturally, a mechanical supporting base can also be swiveled in by the driver based on the indicator. In this case, however, the driver would have to cancel the acoustic or optical indicator before setting the vehicle in operation after ensuring that the supporting base is also in position.
The switches at the hydraulic cylinder are constructed as noncontacting or contacting limit switches or the like and are coupled with a device which likewise carries out a movement or which can be appropriately switched at a stroke of the piston of the cylinder. The limit switch engages after a predefinable piston stroke and the pressure monitoring means in the cylinder are accordingly switched on. The device can act as a rod which is movable parallel to the stroke or as another kind of actuation device, e.g., one which also acts corresponding to the stroke, e.g., an inductive displacement pickup with or without mechanical, fluid or electric signal generation and transmission.
The pressure detection devices in the cylinder can also be constructed as simple pressure switches and, in this case, are preferably arranged in the pressure line to the piston face side or piston ring face side. An arrangement of this kind makes it possible to monitor the pressure switches.
Instead of a simple pressure switch, the pressure detection device can also be provided with means for generating a signal corresponding to, preferably proportional to, the pressure, wherein this signal can be used multiple times. On the one hand, a plain text display can be supplied to the driver in order to provide the driver with information about the working load that the driver currently desires to move, or a scale or weighing device which, if required, may be electronically controlled and also configured in recording mode so that the driver can document the transported loads at the same time. When standardized load carriers, for example, buckets or mandrels which can pick up paper rolls or steel rolls, are used for this purpose, the weight of these load carriers can be accounted for at the same time and subtracted as tare weight from the load to be picked up in order to arrive at the working load.
Naturally, it is important, especially for road transport, that the driver knows what working load he is transporting so as not to exceed the permissible vehicle weights, for example, on bridges.
In the event that the pressure detection device is only constructed as a pressure switch, a pressure switch of this type can be used to block the movement elements or the hydraulic system of the vehicle, or the vehicle can be halted in general. In such cases, the blocking means would have to be connected with a key-operated switch in order to allow the driver to set the vehicle in motion again after an appropriate correction of the load to be picked up or to operate the device within certain limits up to a predetermined reference value, which might often be necessary for emergencies.
Insofar as the heavy-duty vehicle is to be used, for example, as a device similar to a slag transporter, gripping devices acting in parallel on both sides of the heavy-duty vehicle with a corresponding rear swiveling device for buckets or the like load carriers are usually used. In order to prevent one-sided loading, the hydraulic cylinders could be provided with corresponding pressure detection devices and/or limit switches on both sides. This may only be necessary if no precautions have been taken by means of appropriate simultaneous-running or synchronizing elements such as connectors for the gripper devices mounted at both sides or corresponding torsion elements which distribute the load over the vehicle.
The vehicle according to the invention can be used in particular as a slag transport vehicle for picking up slag buckets on a loading platform, since handling of hot slag is hazardous and the suggested tipping-prevention devices substantially prevent incorrect operation.
The invention will be described more fully with reference to schematic drawings.